Remove the connection to external data and add data validation.

Display the Queries & Connections pane and delete the connection to BoydLogisticsTxt$-04.$ The data remains in the worksheet.

Delete the contents of cells A$6$:F$61$ on the RouteDataTemplate sheet.

Select cells C$6$:D$61$ and add a data validation list using the Cities range.

Test your data validation and delete test or sample data.

Select cell A$6.$